Heat-engine.



H. A. LEFEVRE.

HEAT ENGINE.

APPLICATION FILED MAR. 27. 1917.

'Patented July 24, 1917.

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HENRY ANTOINE LEFEVRE, OF PARIS, FRANCE.

Hear-ENGINE.

Specification of Letters Patent.

Patented Jury 24, reir.

Application led March 27, 1917. Serial No. 157,811.

To all whom t may concern:

Be it known that I, HENRY ANTOINE Lnrnviui, a citizen of the United States of America, residing at Paris, France, have inrented. new and useful Improvements in Heat-Engines, of which the following is a specification.

In order to increase the duty of heat cngines, it is usual to heat the compressed-air motor-cylinders in such a manner as to ob tain a better utilization of this air. f

In practice this superheating is limited by the fact that the best oils for lubricating the pistons and the motor-cylinders burn when they are raised to a temperature above about 250 degrees C.

On the other hand, when the superheating reaches a somewhat high degree, it produces during the admission period a premature eX- pansion of the compressed air, which eX- pands in the valve chest and admissionports, which causes a part of the benefit of superheating the air during its expansion in the cylinder to be lost.

The present invention has for its object improvements in heat engines, having for their object to enable the superheating of the air during its expansion to be increased at will without having to fear injury to the pistons and cylinders and of avoiding the premature expansion of the compressed air while it is being admitted into the motorw cylinders.

These improvements consist essentially:

l.. ln thermally insulating the upper part of the cylinder where the compressed air is admitted; the capacity of the part of the cylinder thus insulated corresponding to the weight of air that should normally be admitted into this cylinder.

2. In thermally insulating the part of the cylinder around which the hot fluid circulates, and in dividing the piston into two parts which are also thermally insulated from one another, the part of this piston working in the superheated part of the cylinder and in the upper insulated part of the latter being of a diameter less than that of the cylinder-bore.

By this arrangement, the temperature of the air can be raised to a degree much higher than with the arrangements heretofore usual, since a part of the lubricant can be dispensed with in the superheated part of the engine by reason of the annular space left between the cylinder and the piston, and on the other hand, the premature expansion of the air is no longer to be feared since the upper part 0f the cylinder where the admission takes place insulated thermally in such a manner that its temperature is not greater than that of the air at the moment of such admission.

The invention is shown by way of example in the accompanying drawing, wherein:

Figure l shows in vertical section a heat engine, of which the superheated part of the cylinder is insulated thermally from the rest of said cylinder.

Fig. 2 also shows in vertical section an engine, the upper and lower parts of which are insulated thermally.

As shown in Fig. l of the drawing, the cylinder' of the engine is divided transversely into two parts; a lower part a connected to the gear-case and in which the piston moves in the usual manner, and an upper part a insulated thermally from the iirst by a joint c of any suitable material.

Around this upper part of the cylinder, there is arranged an annular chamber ci in which circulates a hot fluid such as the exhaust gases from a petrol or gas engine, or a liquid raised to a high temperature, etc.

In the cylinder so arranged, there moves a piston also divided into two parts: a lower part e connected by a rod f to the engineshaft g, and an upper part or false piston e insulated thermally from the piston proper e by a disk 71, of insulating material.

The false piston e alone works in the upper superheated part a of the cylinder and the diameter of this false piston is less than that of the bore of the cylinder so thatan annular space is left between the two parts, such space permitting the employment of a lubricant between them to be dispensed with.

By this arrangement, only the upper part a of the cylinder will be raised to a high temperature by the super-heated fluid circulating in the chamber cl, and only the false piston c moving without lubricant in this upper part of the cylinder will be subjected to the action of the heat.

Under these conditions, it is possible to raise the temperature of the upper part a of the cylinder as desired and consequently that of the internal air without interfering with the efficient operation of the lower cylinder a and of the piston proper e.

' gine yto explosion-engines,

, Way of example,

In order to avoid premature expansionof the compressed air admitted into the cylin- Into the upper part a2 ofthe cylinder there opens the admission port y' for comair. The internal dimensions of this part a2 of the cylinder correspond to the Weight of the air which should normally be admitted at each cylinder-charge.

The false piston e carried by the piston e and separated from the latter by the insulating joint 7L, is of a diameter less than that of the bore of the cylinderin order to permit the use of lubricant to be'dispensed with, as has beeny explained above. The height of this false piston is such that it comes, at the end oi'f its stroke, into the upper part a2 of the cylinder.

By this arrangement, although the temperature of the superheating fluid can be raised at will, the compressed air at f the moment of its admission into the cylinder will not be raised in temperature so as to effect itsy premature expansion, since all the air necessary for afcylinder-charge is admitted into the part a2 of the engine,fwhich is insulated thermally from the rest of the latter and of which the temperature is not greater than that ofthe air at the moment of its admission. f

Under these conditions, my improved enenables a maximum Weight of air to be admitted for eachl cylinder-charge, which in conjunction with the yhigh temperature to Which it is then submitted, insures coniplete eXpansion of this air inthe cylinder and perfect operation of theengine.

As mentioned above, the insulating joints c, h and i can pressed be of any suitable material.

The effect of these joints can be regulated by suitably varying their thickness. v

The present invention can also be applied to all types of heat engines, more especially for the purpose above specified. y,

The above arrangements 'are only given by the forms, dimensions and detail arrangements can bevaried according to particular cases Without departing from the nature of the invention. f

Copies of `this. patent may beV obtained for Vhat I claim is:

1. In a heat engine the combination of a cylinder consisting of tivo parts, a heat insulator'betvveen said parts, a piston fitting one of said parts, a false piston operating in the ,other part and having a diameter less than the interior diameter of said other part, means for thermally insulating said false piston from said piston, and means for superheating that part onlyV of the cylinder which, contains said false piston.

2. In a heat engine the combination ofa cylinder, means for superheating a part of said cylinder, means for admitting the charge into the outer end of said cylinder, and means for perheated'part and outer the premature expansion of the charge during its admission.

3. In a heat engine the combination of a cylinder divided transversely into three parts which are thermally insulated from one another, an annular chamber for the passage of superlieating fluid surrounding the median part of the cylinder, means for admitting compressed air to the outer end of the cylinder and a joint of a material that is a non-conductor of heat. interposed between the superheated part of the cylinder and said outerend of the latter in order to avoid the pieinature expansion of the air during its admission.

t. In a heat engine the combination of a cylinder divided transversely into three partstliat'are thermally insulated from one another, an annular chamber for the passage of the superheating fluid surrounding f the median part of the cylinder, means for admitting compressed kair to the outer end of the cylinder, `a joint of a material that is thermally insulating said suend for preventing y a non-conductor of heat interposed between the superheated part of the cylinder and the said outer end of the latter in order to avoid the premature expansion of this air during its period of the innerend of the cylinder, a false piston fixed to said piston and of a diameter less than that of the bore of the cylinder such false piston extending into the superheated part of' the Acylinder and into the said outer end vof the latter, and a joint of a material that is a non-conductor of heat interposedbetiveen the piston and the false pisiiENiiY nNfroiNE LEFEVRE. Witness: s f

Ci-iAs. P. PnEssLY.

ve cents each, byaddressng the Commissioner of Patents,

Washington, D. C.

admission, a piston moving in 

